1. Field of the Invention
The disclosure relates generally to optical touch systems and methods for determining positions of objects using the same, and, more particularly to optical touch systems and related methods for determining positions of objects on a touch plane without any side bars installed thereon.
2. Description of the Related Art
Recently, as more and more equipments capable of using touch input operation commands for inputting, in some electronic devices such as smart phones, PDAs, tablet PCs, Ultra Mobile PCs (UMPCs) and so on, a touch screen which is directly touchable may be provided as a main input device for users to control functions thereof. The touch screen is a screen integrated with an optical touch system, which has a touch-sensitive surface comprising sensors in at least one dimension to detect contact and movement of an object (input tool), such as a pen/stylus or finger near or on the touch-sensitive surface. Currently, optical touch system most commonly includes two kinds of shattered glass and reflective display. The shattered glass optical touch system is equipped with reflective edge bars on sides of touch screen, so that when light emitted, reflections from side bars can be used to distribute light on entire touch screen, so in view of its lens, entire touch screen is illuminated. For the shattered glass optical touch system, when an object such as a finger placed on a location of the touch screen, light of the location will be shattered by the finger, hence, in view of its lens, finger position will become a lower laminated area, so from the lower illuminated area, finger position can be found. With reflective display optical touch system, light absorption or light diffusion side bars will be equipped at sides of the touch screen, so that when light emitted, light touches side bars will be absorbed or diffused, so in view of its lens, entire touch screen is dark. For the reflective display type optical touch system, when a finger is placed on the touch screen, light will be reflected from the finger, and the reflected light will be received by lens, hence, in view of its lens, the finger will become a light enhanced area, so from the light enhanced area, the finger position can be found.
For both above-mentioned optical touch systems, however, side bars must be used, in addition to cost increased, complexity in assembling also increased. Further, currently the touch plane agglutination is adopted for most side bar fastening techniques, consequently, shed or distorted side bars problems prone to occur, thereby affecting determination of the object position.